12.2 Flashcards
At the based of the neck, the roots of the brachial plexus converge forming 3 trunks. Name them.
Superior, middle, inferior trunks
Which trunk is made from the combination of C5 and C6 roots
Superior trunk
Which trunk is the continuation of C7?
Middle trunk
Which trunk is formed from the combination of C8 and T1 roots?
Inferior trunk
Anterior (ventral) nerve division supply which muscles?
Flexors and adductors
Posterior (dorsal) nerves supply which muscles?
Posterior (dorsal) nerves supply the extensors + abductors (muscles)
All 3 posterior division from the trunks combine to form which cord?
Posterior cord
The 2 of the anterior division nerves recombine to form which cord?
Lateral cord
Which cord does the anterior division of the inferior trunk form?
Median nerve
Which nerve innervates: Brachialis, biceps brachii, coracobrachialis muscles?
Musculocutaneous nerve
Which nerve innervates teres minor and the deltoid muscles?
Axillary nerve
Which nerve innervates triceps brachii + extensor muscles in posterior forearm?
Radial nerve
Problems with forearm pronation and supination is due to damage to which myotome?
C6
Problems with arm abduction and lateral rotation is due to damage to which myotome?
C5
Problems with arm adduction and medial rotation is due to damage to which myotomes?
C6,7,8
What are the myotomes associated with elbow flexion?
What are the myotomes associated with elbow extension?
o Flex – C5, C6
o Extend – C7, C8
All intrinsic muscles of the hand are innervated by which myotome (motor fibre of single spinal root)?
T1
Weakness of extensors (hand and forearm) and loss of sensation over dorsal web is indicative of injury to which nerve?
Radial nerve
Inability to extend 4th + 5th digits at interphalangeal joints leading to permanent flexion hence a claw, indicates damage to which nerve?
Ulnar nerve (distally).
The closer to the paw, the worse the claw
Explain ulnar paradox
The ulnar nerve also innervates the ulnar (medial) half of the flexor digitorum profundus muscle (FDP).
If the ulnar nerve lesion occurs more proximally (closer to the elbow), the flexor digitorum profundus muscle may also be denervated.
As a result, flexion of the IP joints is weakened, which reduces the claw-like appearance of the hand. (Instead, the fourth and fifth fingers are simply paralyzed in their fully extended position.)
This is called the “ulnar paradox” because one would normally expect a more proximal and thus debilitating injury to result in a more deformed appearance.
Consequences of a median nerve injury
‘Hand of benediction’ when patient attempts to make a fist.
Inability to oppose thumb.
Proximal median nerve injury –> can’t flex 2nd + 3rd fingers.
Distal median nerve injury –> can’t extend 2nd + 3rd fingers
What is Erb’s palsy?
Upper brachial plexus injury
Brachial plexus is stretched due to tractiontion and C5 tears
Affects:
Ability to abduct the shoulder – arm hangs by side
Arm remains pronated – hand tilted backwards
What is a Klumpke’s paresis?
Lower brachial plexus injury Tears
T1
Affects lower myotomes + dermatomes
Affects:
Paralysis of intrinsic hand muscles – claw hand
Numbness of C8-T1 dermatome
What is downward movement of the scapula called?
Depresion
What is forward movement of the scapula around the trunk called?
Protraction
What is backward movement of the scapula around the trunk called?
Retraction
The range of motion of the scapula provides what percentage of the total movement of the upper extremity relative to the body?
1/3rd sometimes more
What runs in the bicipital groove of the humerus?
Tendon of the long head of the biceps
What is the bicipital groove aka?
Inter-tubercular groove - because it runs between the greater + lesser tubercle of the humerus
Which tendon arises from the infraglenoid tubercle?
long head of the triceps
Which tendon arises from the supraglenoid tubercle?
Long head of the biceps
To get to the supraglenoid tubercle, where does the tendon of the long head of the biceps travel along?
It passes inside the joint capsule + right over the top of the head of the humerus
Name the 3 short muscles on the back and 1 on the front that hold the humerus in place
front - subscaularis
back - supraspinatus
back - infraspinatus
back - teres minor
Movement of humerus subscaularis muscles allows?
Internal rotation
Where does the subscapularis arise from?
Almost all of the anterior (costal) aspect of the scapula
Where does subscapularis insert?
Lesser tubercle of the humerus
Where do the rotator cuff muscles insert?
Greater tubercle of humerus EXCEPT subscapularis which inserts into the lesser tubercle
Movement of supraspinatus muscle
Abduction of humerus
Where does the infraspinatus and teres minor muscles originate from?
Infraspinous fossa of scapula
Where does the supraspinatus muscles arise from?
Supraspinous fossa of scapula
Movement of the teres minor and infraspinatus muscles?
External rotation of the humerus
Name the muscle that run from the scapula to the humerus on the back which are not part of the rotator cuff
Teres major
Where does teres major originate and insert?
Origin - lower lateral border of scapulaInsertion - posterior lip of bicipital groove
Movement of teres major
Adductor of humerus
Where does coracobrachialis originate?
Coracoid process
Where does coracobrachialis insert?
On humerus
Movement of coracobrachialis
Helps to flex shoulder joint
How many muscles go from scapula to humerus?
7;
4 short rotator cuff muscles
Teres major
Coracobrachialis
Deltoid
How many muscles hold the scapula in place and move it in relation to the trunk?
6;
4 on back
1 in front
1 underneath
Name the large powerful muscle underneath the scapula that holds it in place
Serratus anterior
Where does the serratus anterior muscle arise from and inserts?
Origin - side + front of first 8 ribsInserts - medial border of scapula
Contraction of the serratus anterior muscle does what movement?
Protrusion of scapula when all of the muscle fibres contracts
Name the 3 smaller and deeper muscles on the back (relative to trapezius) that hold the scapula in place.
Rhomboid major
Rhomboid minor
Levator scapulae
How are joints classified?
Fibrous - limited movement
Cartilaginous - limited movement:
- primary - e.g. 1st costosternal joint
- secondary e.g. pubic symphysis
Synovial - contain synovial fluid
Give an example of a fibrous + synovial joint
Synovial - knee, shoulder
Fibrous - sutures of the skull
What type of joint is the distal tibiofibular joint?
Fibrous
What is articular cartilage?
The normal hyaline carilage covering bony articular surfaces.
It is avascular + derives its nourishment from synovial fluid
What are the surface-palpable surface features of the back?
C7 - vertebra prominens
T7 - inferior angle of scapula
L4 - crests of iliac bones - level of lumbar puncture
What are the parts of the thoracic vertebra?
Body
Pedicles
Superior + inferior articular process
Pars interarticularisSpinous + transverse processes
Lamina
Vertebral foramen for the passage of spinal cordIntervertebral foramen for passage of spinal nerves
What passes in the centre of the vertebral foramen?
Spinal cord
What passes in the centre of the intervertebral foramen?
Spinal nerves
Which vertebra supports the skull?
Atlas
Which articulares inferiorly with the axis
What do the atlas + axis articular?
The axis projects the dens upwards behind the anterior arch of the atlasIt is held in place by the transverse ligament of the atlas
This is the point of rotation for the skull
What type of joints are the elbow and knee joints?
Synovial - hinge
What type of joints are the wrist/ankle joints
Plane
What are the differences between the upper and lower limbs?
Rotation during development:
- upper: external 45 degrees
- lower: internal 90 degrees
Elbow + knee flex in opposite directions
Palm = anterior
Sole = posterior
What does the pectoral gridle consists of?
Clavicle
Scapula
Proximal humerus + their respective joints: sternoclavicular, acromioclavicular, glenohumerus
Name the ligaments of the acromioclavicular joint
Coracoclavicular
Acromioclavicular
Coracoacromial
Function of the corcacoacromial joint
Provides roof for the joint
What are the parts of the humerus?
Upper end:
- head articulates with glenoid cavity
- greater + lesser tubercles
Shaft:
- sprial groove posteiorly
Lower end:
- capitellum (lateral) articulates with radius
- trochlea (medial) articulates with ulna
- medial + lateral epicondyles
What 2 main movemens are possible at the elbow joint?
Flexion/extension
Pronation/supination
What are the boundaries of the cubital fossa?
Medially: pronator teres
Laterally: brachioradialis
Base: imaginary line between the humerual epicondyles
Floor: supinator muscle + brachialis
Roof: skin, fascia + bicipital aponeurosis
From lateral to medial what are the contents of the cubital fossa?
Really Need
Beer To
Be At
My Nicest
Radial nerve
Biceps tendon
Brachial artery
Median nerve
What are the structures felt anteriorly at the wrist?
Medial to lateral:
- Flexor carpi ulnaris tendon
- Ulnar artery
- Flexor digitorum superficialis
- Tendons
- Palmaris longus (can be absent)
- Flexor carpi radialis tendon- radial artery
- Brachialis tendon
What lies in the anatomical snuff box?
Radial artery
Superficial branch of radial nerve
Scaphoid bone
What is fascia?
A sheet or band of fibrous tissue lying deep to the skin that lines, invests + separated structures within the body.
It covers the muscles + helps divide the muscular sections into compartment
Name the 5 muscle groups that produce movement of the hip joint.
Short rotaters
Flexors
Abductors
Adductors
Extensors
Name the short hip rotator muscle
Piriformis
Obturator externus
Obturator internus
Gemellus muscles, superior + inferior
Quadratus femoris muscle
Which short hip rotator muscle arises from the scarum?
Piriformis
What does the piriformis muscle pass through as it leaves the pelvis
Passes through the greater sciatic foramen along w/ the sciatic nerve
All short rotator muscles pull the back of the femur medially producing which movement?
Lateral rotation of hip joint
Name the 3 extracapsular ligaments of the hip joint
Iliofemoral
Pubofemoral
Ischiofemoral
Describe the shapes of the 3 extracapsular ligaments of the hip joint
Iliofemoral - Y shaped.
Pubofemoral - triangular.
Ischiofemoral - spiral orientation.
Which movements does the extracapsular ligaments of the hip joint prevent?
Iliofemoral + ischiofemoral - excessive extension.
Pubofemoral - excessive abduction + extension
Name the intracapsular ligament of the hip joint
Ligament of the head of femur aka ligamentum teres femoris
Which ligament of the hip joint encloses a branch of the obturator artery?
Ligament of the head of femur aka ligamentum teres femoris
Arterial supply of hip joint is largely via which arteries?
Medial + lateral circumflex femoral arteries - which are branches of the profunda femoris artery (deep femoral artery)
Which of the circumflex femoral arteries is responsible for the majority of the arterial suply?
Medial circumflex femoral artery
What can damage to the medial circumflex femoral artery lead to?
Avascular necrosis of the femoral head
Name the 4 nerves which innervate the hip joint
Femoral nerve.
Obturator nerve.
Superior gluteal nerve
Nerve to quadratus femoris
Which ligament is most anterior out of the iliofemoral, pubofemoral and ischiofemoral ligaments?
Iliofemoral ligament
Which ligament is most posterior out of the iliofemoral, pubofemoral and ischiofemoral ligaments?
Ischiofemoral ligament
What is DDH?
Developmental dysplasia of the hipIt occurs when hip joint does not develop properly in utero
Name the common clinical features of DDH
Limited abduction at the hip joint.
Limb length discrepancy – the affected limb is shorter.
Asymmetrical gluteal or thigh skin folds
Treatment of DDH
Pavlik harness.
This holds the femoral head in the acetabular fossa + promotes noramal development of the hip joint
Alternative treatment option for DDH if Pavlik harness ineffective
Surgery
Hip dislocation is rare but name the 2 main types of acquired hip dislocation
Posterior dislocation.
Anterior dislocation (more rare)
Describe posterior hip dislocation
Femoral head is forced posteriorly + tears through the inferior + posterior part of the joint capsule, where it is at its weakest.
Affected limb becomes shortened + medially rotated
Describe the clinical presentation of a hip fracture vs a hip posterior dislocation
Fracture - The affected leg is externally rotated and may be shortened
Dislocation - The affected limb becomes shortened and medially (internally) rotated.
What is an anterior dislocation of the hip joint often associated with?
Fractures of the femoral head
Which type of fascia does this describe: bends with the reticular layer beneath the dermis
Superficial fascia
Which type of fascia provides membranous investments that suspend organs within their cavities
Visceral fascia
Which type of fascia envelopes muscles, bones and neurovascular structures
Deep fascia
What is fascia lata?
A deep fascial investment of the whole thigh musculaature + is analogous to a strong, extensible, elasticated stocking
Where is the coracoid process found?
Scapula
What fracture of the humerus can lead to Volkmanns contracture?
Supra-condylar fracture.
Interferes with the supply of the brachial artery
The tendon of which muscle runs in the intertubercular groove?
Long head of biceps brachii
Where does pectoralis major attach to?
Intertubercular sulcus (not groove)
Name the 3 thenar muscles
Opponens pollicis
Abductor pollicis brevis
Flexor pollicis brevis
Action of opponens pollicis muscle
Opposes thumb by medially rotating + flexing the metacarpal on the trapezium
Which thenar muscle is the largest?
Oppenens pollicis
Which muscle is found anteriorly to the opponens pollicis + proximally to the flexor pollicis brevis?
Abductor pollicis brevis
What is the action of flexor pollicis brevis?
Flexes the metacarphophalangeal joint of the thumb
Which thenar muscle is the most distal?
Flexor pollicis brevis
What produces the hypothenar eminence?
Hypothenar muscles:
- Opponens digiti minimi
- Abductor digiti minimi
- Flexor digiti minimi brevis
Which hypothenar muscle lies deep to the others?
Opponens digit minimi
Which hypothenar muscle is most superficial?
Abductor digiti minimi
Which hypothenar muscle lies laterally to the abductor digiti minimi?
Flexor digiti mini brevis
Which nerve innervates all hypothenar muscles?
Ulnar nerve
Which muscle rotates the metacarpal of. the little finger towards the palm, producing opposition?
Opponens digiti minimi
How many lumbricals are there in the hand?
4, each associated with a finger
Where do lumbricals originate from?
A tendon of the flexor digitorum profundus
Where does lumbricals insert?
Into the extensor hood (once the’ve passed dorsally + laterally around each finger from origin)
What are the actions of the 4 lumbricals found in the hand?
All flex at the MCP joint + extend at the interphalangeal joints of each finger
What is the innervation of the lumbricals?
The lateral 2 (of the index + middle fingers) = median nerve.
Medial 2 lumbricals (of little + ring fingers = ulnar nerve
Which lumbricals are unipennate + which are bipennate?
I + II are unipennate.
III + IV are bipennate.
Define unipennate
Fascicles insert into only 1 side of the tendon
Define bipennate
Fascicles insert into the tendon from opposite sides
Define multipennate
Fascicles attach obliquely from many directions to several tendons
Where are interossei muscles located?
Between the metacarpals
Into which 2 groups can the interossei muscles be divided?
Dorsal + palmar interossei
What action does dorsal interossei do?
Abduction of the fingers at the MCP joint
What action does palmar interossei do?
Adduction of the. fingers at the MCP joint
Which nerve innervate the interossei muscles?
Ulnar nerve
What is the action of the adductor pollicis muscle?
Adductor of thumb
What is the deep palmar arch formed by?
Radial artery passes anteriorly through the space between the 2 heads of adductor pollicis
What is the action of palmaris brevis?
Wrinkles skin of hypothenar eminence + deepens the curvature of the hand Improving grip
Describe the shape of the palmaris brevis muscle
Small thin, found very superficially in the subcutaneous tissue of hypothenar eminence
Describe the shape of the adductor pollicis muscle
Large triangular with 2 heads
Which nerve innervates the medial 2 lumbricals?
Ulnar nerve
What action does the lumbricals have on the MCP joints?
Flexion
What is the action of the dorsal interoseei?
Abduction of the fingers
What is. the action of palmaris brevis?
Deepen the curvature of the hand
What is the action of the dorsal interoseei?
Abduction of the fingers
What action does the lumbricals have on the MCP joints?
Flexion
Name 2 muscles in the palm that are not lumbricals or interossei + do not fit in the hypothenar + thenar compartments
Palmaris brevis
Adductor pollicis
Both innervated by ulnar nerve
How many palmar interossei muscles are there?
3
How many dorsal interossei muscles are there?
4
Which nerve innervate the interossei muscles?
Ulnar nerve
What action does palmar interossei do?
Adduction of the. fingers at the MCP joint
What action does dorsal interossei do?
Abduction of the fingers at the MCP joint
In addition to their actions of abduction (dorsal interossei) + adduction (palmar interossei), what do the interossei muscles also assist in
Flexion of lumbricals MCP joints.
Extension at IP joints.
List 7 types of fascicles in muscles.
Circular
Convergent
Parallel
Unipennate
Multipennate
Fusiform
Bipennate
Define multipennate
Fascicles attach obliquely from many directions to several tendons
Define bipennate
Fascicles insert into the tendon from opposite sides
Define unipennate
Fascicles insert into only 1 side of the tendon
Which muscle flexes the MCP joint of the little finger?
Flexor digiti minimi brevis
Which muscle abductors the little digit?
Abductor digiti minimi
Which nerve innervates all hypothenar muscles?
Ulnar nerve
Which thenar muscle is the largest?
Oppenens pollicis
